The "teleports" talked about in the dbb forum are a graphical illusion that only works with the original Descent engine. You basically disconnect one side of a segment that is surrounded by other segments and connect it to another segment that is floating freely in that "room" made by those aforementioned segments. This however is not what you are looking for, and it doesn't really work with an OpenGL based renderer (at least not with D2X-XL's). However, unlike one contributor to that thread claimed, there is no increased risk of crashing when playing a "4D" level.